Typical utility-scale wind turbines include a plurality of rotor blades which radially extend from a central rotor hub. The combined assembly of the rotor blades and the rotor hub is generally referred to as the rotor. The rotor blades aerodynamically interact with wind energy, creating lift and drag, which the rotor hub then translates into a driving torque. The driving torque is communicated from the rotor hub through a main shaft that is coupled to the rotor hub. The rotational torque is then distributed to one or more generators via a drivetrain, which in turn produce electric power to be processed and transmitted to an associated electrical grid. The main shaft, the drivetrain and the generators are all situated within a nacelle that is located on top of a tower.
Within the drivetrain, the main shaft communicates any driving torque introduced by wind energy to one or more generators through one or more drive chains. More specifically, rotation of the main shaft causes rotation of one or more drive sprockets rigidly coupled thereto. The drive sprockets rotatably engage the drive chains, which further engage one or more driven sprockets that are rigidly coupled to generator inputs. In wind turbine applications having a plurality of generators that are driven by the single main shaft, multiple sets of drive sprockets and corresponding sets of drive chains are provided on the main shaft where each set of drive sprockets and chains is configured to drive a different generator.
Such drive chains are typically constructed with a plurality of moving components or links, the ends of which are mechanically joined to form a closed loop around the drive and driven sprockets. During use, and as the drive chains are rotated onto and off of the sprockets, the individual links of the drive chains pivot relative to adjacent links, thus abutting and mechanically sliding against one another. Such mechanical interactions between the individual links of the drive chains cause a substantial amount of friction, and thus, significant losses in energy transfer between the main shaft and the associated generators. The energy lost in each drive chain, which may further be compounded in applications employing several sets of drive chains for driving multiple generators, may significantly reduce the overall efficiency of the wind turbine.
Accordingly, it would be beneficial to provide a drive chain which alleviates some of the disadvantages of conventional drive chain assemblies. Specifically, there is a need for a drive chain with links which form joints having smaller areas of contact so as to reduce mechanical interactions therebetween during use. Moreover, there is a need to reduce the amount of overall friction generated within the drive chain so as to increase the efficiency of energy transfer between the main shaft and the generators of a wind turbine.